bug#58168: string-lessp glitches and inconsistencies

["Mattias Engdegård" <mattias.engdegard@gmail.com>]

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1 okt. 2022 kl. 15.43 skrev Lars Ingebrigtsen <larsi@gnus.org>:

> There was a very long thread about changing this output in a bug report
> somewhere, and we decided not to, because all the alternatives were
> worse than what we have.

I have no wish to reopen old wounds (and it sounds as if the debate isn't one that you are keen to revisit), but I'm a bit surprised -- it all arises because of old code that still treats raw bytes as Latin-1, and I know that neither of you are very fond of that either.

1 okt. 2022 kl. 15.51 skrev Eli Zaretskii <eliz@gnu.org>:

> I think the variable is a misnomer of sorts: the request back when it
> was introduced to display hex where we usually display octal \nnn
> escapes.  And the latter happens not only for raw bytes.

Fair enough. Maybe the documentation should reflect that, but I'm still holding out for a change to the C1 presentation in the long term, so...

I'm not going to pursue this little digression any further except that while looking at it I found a few inaccuracies and a likely bug in redisplay-testsuite.el. I'm attaching a patch which un-muddles the test and adds a display of unprintable Unicode chars such as C1 controls, in addition to raw bytes. I'd like to adorn the commit with the correct bug number so if you remember that of the original discussion that would be useful (I never found it very easy to search debbugs).


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diff --git a/test/manual/redisplay-testsuite.el b/test/manual/redisplay-testsuite.el
index 01b0a895a4..5495146b87 100644
--- a/test/manual/redisplay-testsuite.el
+++ b/test/manual/redisplay-testsuite.el
@@ -305,7 +305,7 @@ test-redisplay-5-toggle
   (let ((label (if display-raw-bytes-as-hex "\\x80" "\\200")))
     (overlay-put test-redisplay-5a-expected-overlay 'display
                  (propertize label 'face 'escape-glyph)))
-  (let ((label (if display-raw-bytes-as-hex "\\x3fffc" "\\777774")))
+  (let ((label (if display-raw-bytes-as-hex "\\xfc" "\\374")))
     (overlay-put test-redisplay-5b-expected-overlay 'display
                  (propertize label 'face 'escape-glyph))))
 
@@ -320,18 +320,36 @@ test-redisplay-5
         (test-insert-overlay " " 'display "\200"))
   (insert "\n\n")
   (insert "  Expected: ")
-  ;; This tests a large codepoint, to make sure the internal buffer we
-  ;; use to produce the representation is large enough.
-  (aset printable-chars #x3fffc nil)
   (setq test-redisplay-5b-expected-overlay
         (test-insert-overlay " " 'display
-                             (propertize "\\777774" 'face 'escape-glyph)))
+                             (propertize "\\374" 'face 'escape-glyph)))
   (insert "\n    Result: ")
   (setq test-redisplay-5b-result-overlay
-        (test-insert-overlay " " 'display (char-to-string #x3fffc)))
+        (test-insert-overlay " " 'display (char-to-string #x3ffffc)))
+  (insert "\n\n")
+  (insert-button "Toggle between octal and hex display for raw bytes"
+                 'action 'test-redisplay-5-toggle)
+  (insert "\n\n"))
+
+(defun test-redisplay-6 ()
+  (insert "Test 6: Display of unprintable Unicode chars:\n\n")
+  (insert "  Expected: ")
+  (test-insert-overlay " " 'display
+                       (propertize "\\200" 'face 'escape-glyph))
+  (insert "  (representing U+0100)")
+  (insert "\n    Result: ")
+  (test-insert-overlay " " 'display "\u0080")
   (insert "\n\n")
-  (insert-button "Toggle between octal and hex display"
-                 'action 'test-redisplay-5-toggle))
+  ;; This tests a large codepoint, to make sure the internal buffer we
+  ;; use to produce the representation is large enough.
+  (insert "  Expected: ")
+  (aset printable-chars #x10abcd nil)
+  (test-insert-overlay " " 'display
+                       (propertize "\\4125715" 'face 'escape-glyph))
+  (insert "  (representing U+0010ABCD)")
+  (insert "\n    Result: ")
+  (test-insert-overlay " " 'display "\U0010ABCD")
+  (insert "\n\n"))
 
 (defun test-redisplay ()
   (interactive)
@@ -349,6 +367,7 @@ test-redisplay
     (test-redisplay-3)
     (test-redisplay-4)
     (test-redisplay-5)
+    (test-redisplay-6)
     (goto-char (point-min))))
 
 ;;; redisplay-testsuite.el ends here